Androgenetic alopecia is a common form of hair loss in both men and women. In men, this condition is also known as “male-pattern baldness” or pattern hair loss. This form of hair loss affects an estimated 60 million men in the United States alone. Although risk factors contributing to this condition are still being studied, researchers have determined that androgenetic alopecia is related to hormones called androgens, and particularly to an androgen called dihydrotestosterone. Increased levels of androgens in hair follicles can lead to a shorter cycle of hair growth, as well as the growth of shorter and thinner strands of hair. A majority of men regard baldness as an unwanted and distressing experience. Although baldness attributable to androgenetic alopecia is not as common in women as in men, the psychological effects of hair loss tend to be much greater for women. Although androgenic alopecia may not be the main cause of hair loss in most women, female hair loss has been reported to affect around 20 million women in the United States.
Early stages of hair loss can be slowed or reversed with medication. FDA-approved drugs include minoxidil and finasteride. Other treatment options include tretinoin combined with minoxidil, ketoconazole shampoo, and spironolactone. Advanced cases of hair loss may be resistant or unresponsive to pharmaceutical therapy. A number of patients elect to undergo surgical hair transplantation.
Various phototherapy devices for addressing androgenetic alopecia have been developed. The term “phototherapy” relates to the therapeutic use of light. Without necessarily being directed to treatment of hair loss, various light therapies (e.g., including low level light therapy (LLLT) and photodynamic therapy (PDT)) have been publicly reported or claimed to provide various health related medical benefits—including, but not limited to: treating skin or tissue inflammation; promoting tissue or skin healing or rejuvenation; enhancing wound healing; pain management; reducing wrinkles, scars, stretch marks, varicose veins, and spider veins; enhancing mood; treating microbial infections; treating hyperbilirubinemia; and treating various oncological and non-oncological diseases or disorders.
Various mechanisms by which phototherapy has been suggested to provide therapeutic benefits include: increasing circulation (e.g., by increasing formation of new capillaries); stimulating the production of collagen; stimulating the release of adenosine triphosphate (ATP); enhancing porphyrin production; reducing excitability of nervous system tissues; stimulating fibroblast activity; increasing phagocytosis; inducing thermal effects; stimulating tissue granulation and connective tissue projections; reducing inflammation; and stimulating acetylcholine release. Phototherapy has also been suggested to stimulate cells to generate nitric oxide. Various biological functions attributed to nitric oxide include roles as signaling messenger, cytotoxin, antiapoptotic agent, antioxidant, and regulator of microcirculation. Nitric oxide is recognized to relax vascular smooth muscles, dilate blood vessels, inhibit aggregation of platelets, and modulate T cell-mediate immune response. Nitric oxide is produced by multiple cell types in skin, and is formed by the conversion of the amino acid L-arginine to L-citrulline and nitric oxide, mediated by the enzymatic action of nitric oxide synthases (NOSs).
One example of a commercially available phototherapy device intended for addressing hair loss is the iGrow® laser hair rejuvenation system (Apira Science, Boca Raton, Fla., US), which embodies a rigid helmet (similar in appearance to a bicycle helmet) utilizing a combination of red laser diodes and light emitting diodes operating at 655 nm±5 nm. Another example of a commercially available phototherapy device intended for addressing hair loss is the Theradome™ LH80 Pro helmet (similar in appearance to a bicycle helmet), which utilizes 80 lasers with a peak wavelength of 678 nm (Theradome, Inc., Pleasanton, Calif., US). Yet another example of a commercially available phototherapy device intended for addressing hair loss is the Capillus® laser cap (Capillus LLC, Miami, Fla., US) embodying a rigid cap insert with 272 laser diodes operating at 650 nm arranged to fit beneath a conventional head covering such as a baseball cap, a headscarf, or a beanie. Other commercially available phototherapy devices intended for addressing hair loss include laser combs, such as the Hairmax® laser comb (Lexington Int., LLC, Boca Raton, Fla., US). Various Hairmax® laser combs utilize 7 to 12 laser modules operating at 655 nm±10 nm.
Existing phototherapy devices have limitations that affect their utility. Rigid helmet-type phototherapy devices may be uncomfortable and unsightly for many users, and such devices may be cumbersome to manufacture. Providing substantially uniform and/or uninterrupted coverage over an entire area to be treated may also be challenging for conventional phototherapy helmets, caps, and combs (e.g., as they require user movement and compliance). Thermal management may also be a concern for conventional phototherapy helmets and caps.
The art continues to seek improved phototherapy devices providing desirable illumination characteristics and capable of overcoming challenges associated with conventional phototherapy devices.